FIG. 12 is a front elevation view of a conventional thin type hoisting machine for an elevator, disclosed in JP 2000-289954 A, for example, FIG. 13 is a cross sectional view for explaining a structure of the hoisting machine, and FIG. 14 is an enlarged view of a vicinity of a stator core of a motor section of the elevator hoisting machine.
A fixed main shaft 2 is securely fastened to a cup shape housing 1. A sheave 4, which is a portion of a rotation member 5, is mounted about the fixed main shaft 2, through a bearing 3. The housing 1 has a shape that covers the sheave 4, and a main rope that hauls the elevator enters and exits through an opening portion 1a opened in a portion of the housing 1. One end of a side opposite to a position at which the fixed main shaft 2 and the housing 1 are securely fastened together becomes a cylindrical rotor mounting portion 6a of a rotation support frame 6. A rotor 7 is mounted to the cylindrical rotor mounting portion 6a. There is a stator 8 in an inner diameter portion of the housing 1 opposite to the rotor 7 with a small space. The rotor 7 and the stator 8 form a motor that causes the sheave 4 to rotate. Further, a support frame 9 is securely fastened to one end of the cup shape housing 1 opposite to the position at which the cup shape housing 1 and the fixed main shaft 2 are securely fastened together. A brake frame 10a of a brake device 10 is attached to the support frame 9, making an inner diameter surface of the cylindrical rotor mounting portion 6a into a braking surface. A brake shaft 10b supported by the brake frame 10a is pushed onto an inner circumferential surface of the cylindrical rotor mounting portion 6a. The brake shaft 10b brakes rotation of the sheave 4. Further, a rotation shaft 11 is attached in the vicinity of the rotation center of the side having the cylindrical rotor mounting portion 6a of the rotation support frame 6. The rotation shaft 11 is joined to a rotation shaft 12a of an encoder 12 attached to the support frame 9.
A magnet 13 of the rotor 7 is expensive, and normally a width M1 of the magnet 13 of the rotor 7 is not made equal to or larger than a width C1 of a core 8a. Accordingly, a width W1 of the motor section of the thin type hoisting machine is substantially determined by the sum total of the dimension C1 of the core 8a of the stator 8, dimensions E1 and E1 of ends of a coil 14, and a plate thickness S1 of the support frame 9.
Conventional thin type elevator hoisting machines are structured as described above, and are thin in comparison with the previous elevator hoisting machines. However, the torque necessary for the elevator hoisting machine becomes larger, and although the elevator hoisting machine can be called thin, the absolute thickness gradually becomes larger.
With machine room-less elevators, arranging an elevator hoisting machine in a gap between a car within a hoistway and a hoistway wall is customary. However, the amount of space occupied as the hoistway, the so-called dead space within the hoistway, increases, whether or not in actual use, with increasing thickness of the elevator hoisting machine. Consequently, it is necessary to make the thin type elevator hoisting machine thinner.